/*
 * Copyright 2005 Bytecode Pty Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jooq.tools.csv;

import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * A very simple CSV reader released under a commercial-friendly license.
 *
 * @author Glen Smith
 */
public class CSVReader implements Closeable, Iterator<String[]> {

    private BufferedReader  br;
    private boolean         hasNext            = true;
    private CSVParser       parser;
    private int             skipLines;
    private boolean         linesSkiped;

    /**
     * The default line to start reading.
     */
    public static final int DEFAULT_SKIP_LINES = 0;

    /**
     * Constructs CSVReader using a comma for the separator.
     *
     * @param reader the reader to an underlying CSV source.
     */
    public CSVReader(Reader reader) {
        this(reader, CSVParser.DEFAULT_SEPARATOR, CSVParser.DEFAULT_QUOTE_CHARACTER, CSVParser.DEFAULT_ESCAPE_CHARACTER);
    }

    /**
     * Constructs CSVReader with supplied separator.
     *
     * @param reader the reader to an underlying CSV source.
     * @param separator the delimiter to use for separating entries.
     */
    public CSVReader(Reader reader, char separator) {
        this(reader, separator, CSVParser.DEFAULT_QUOTE_CHARACTER, CSVParser.DEFAULT_ESCAPE_CHARACTER);
    }

    /**
     * Constructs CSVReader with supplied separator and quote char.
     *
     * @param reader the reader to an underlying CSV source.
     * @param separator the delimiter to use for separating entries
     * @param quotechar the character to use for quoted elements
     */
    public CSVReader(Reader reader, char separator, char quotechar) {
        this(reader, separator, quotechar, CSVParser.DEFAULT_ESCAPE_CHARACTER, DEFAULT_SKIP_LINES,
            CSVParser.DEFAULT_STRICT_QUOTES);
    }

    /**
     * Constructs CSVReader with supplied separator, quote char and quote
     * handling behavior.
     *
     * @param reader the reader to an underlying CSV source.
     * @param separator the delimiter to use for separating entries
     * @param quotechar the character to use for quoted elements
     * @param strictQuotes sets if characters outside the quotes are ignored
     */
    public CSVReader(Reader reader, char separator, char quotechar, boolean strictQuotes) {
        this(reader, separator, quotechar, CSVParser.DEFAULT_ESCAPE_CHARACTER, DEFAULT_SKIP_LINES, strictQuotes);
    }

    /**
     * Constructs CSVReader with supplied separator and quote char.
     *
     * @param reader the reader to an underlying CSV source.
     * @param separator the delimiter to use for separating entries
     * @param quotechar the character to use for quoted elements
     * @param escape the character to use for escaping a separator or quote
     */

    public CSVReader(Reader reader, char separator, char quotechar, char escape) {
        this(reader, separator, quotechar, escape, DEFAULT_SKIP_LINES, CSVParser.DEFAULT_STRICT_QUOTES);
    }

    /**
     * Constructs CSVReader with supplied separator and quote char.
     *
     * @param reader the reader to an underlying CSV source.
     * @param separator the delimiter to use for separating entries
     * @param quotechar the character to use for quoted elements
     * @param line the line number to skip for start reading
     */
    public CSVReader(Reader reader, char separator, char quotechar, int line) {
        this(reader, separator, quotechar, CSVParser.DEFAULT_ESCAPE_CHARACTER, line, CSVParser.DEFAULT_STRICT_QUOTES);
    }

    /**
     * Constructs CSVReader with supplied separator and quote char.
     *
     * @param reader the reader to an underlying CSV source.
     * @param separator the delimiter to use for separating entries
     * @param quotechar the character to use for quoted elements
     * @param escape the character to use for escaping a separator or quote
     * @param line the line number to skip for start reading
     */
    public CSVReader(Reader reader, char separator, char quotechar, char escape, int line) {
        this(reader, separator, quotechar, escape, line, CSVParser.DEFAULT_STRICT_QUOTES);
    }

    /**
     * Constructs CSVReader with supplied separator and quote char.
     *
     * @param reader the reader to an underlying CSV source.
     * @param separator the delimiter to use for separating entries
     * @param quotechar the character to use for quoted elements
     * @param escape the character to use for escaping a separator or quote
     * @param line the line number to skip for start reading
     * @param strictQuotes sets if characters outside the quotes are ignored
     */
    public CSVReader(Reader reader, char separator, char quotechar, char escape, int line, boolean strictQuotes) {
        this(reader, separator, quotechar, escape, line, strictQuotes, CSVParser.DEFAULT_IGNORE_LEADING_WHITESPACE);
    }

    /**
     * Constructs CSVReader with supplied separator and quote char.
     *
     * @param reader the reader to an underlying CSV source.
     * @param separator the delimiter to use for separating entries
     * @param quotechar the character to use for quoted elements
     * @param escape the character to use for escaping a separator or quote
     * @param line the line number to skip for start reading
     * @param strictQuotes sets if characters outside the quotes are ignored
     * @param ignoreLeadingWhiteSpace it true, parser should ignore white space
     *            before a quote in a field
     */
    public CSVReader(Reader reader, char separator, char quotechar, char escape, int line, boolean strictQuotes,
        boolean ignoreLeadingWhiteSpace) {
        this.br = new BufferedReader(reader);
        this.parser = new CSVParser(separator, quotechar, escape, strictQuotes, ignoreLeadingWhiteSpace);
        this.skipLines = line;
    }

    /**
     * Reads the entire file into a List with each element being a String[] of
     * tokens.
     *
     * @return a List of String[], with each String[] representing a line of the
     *         file.
     * @throws IOException if bad things happen during the read
     */
    public List<String[]> readAll() throws IOException {

        List<String[]> allElements = new ArrayList<>();
        while (hasNext) {
            String[] nextLineAsTokens = readNext();
            if (nextLineAsTokens != null)
                allElements.add(nextLineAsTokens);
        }
        return allElements;

    }

    /**
     * Reads the next line from the buffer and converts to a string array.
     *
     * @return a string array with each comma-separated element as a separate
     *         entry.
     * @throws IOException if bad things happen during the read
     */
    public String[] readNext() throws IOException {
        String[] result = null;
        do {
            String nextLine = getNextLine();
            if (!hasNext) {
                return result; // should throw if still pending?
            }
            String[] r = parser.parseLineMulti(nextLine);
            if (r.length > 0) {
                if (result == null) {
                    result = r;
                }
                else {
                    String[] t = new String[result.length + r.length];
                    System.arraycopy(result, 0, t, 0, result.length);
                    System.arraycopy(r, 0, t, result.length, r.length);
                    result = t;
                }
            }
        }
        while (parser.isPending());
        return result;
    }

    /**
     * Reads the next line from the file.
     *
     * @return the next line from the file without trailing newline
     * @throws IOException if bad things happen during the read
     */
    private String getNextLine() throws IOException {
        if (!this.linesSkiped) {
            for (int i = 0; i < skipLines; i++) {
                br.readLine();
            }
            this.linesSkiped = true;
        }
        String nextLine = br.readLine();
        if (nextLine == null) {
            hasNext = false;
        }
        return hasNext ? nextLine : null;
    }

    /**
     * Closes the underlying reader.
     *
     * @throws IOException if the close fails
     */
    @Override
    public void close() throws IOException {
        br.close();
    }

    // ------------------------------------------------------------------------
    // XXX: Iterator implementation added by Johannes Buehler
    // ------------------------------------------------------------------------

    @Override
    public boolean hasNext() {
        return hasNext;
    }

    @Override
    public String[] next() {
        try {
            return readNext();
        }
        catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException("remove() method is not supported for CSV Iterator ");
    }
}
